The benefits of open water induction and top spots to start
Swimmer advice
You should feel confident swimming your chosen distance in a pool and have some experience in open water.
The route will be clearly marked with large buoys, and our water safety team will be on hand to help if needed.
If you're new to open water swimming, check out our training guides below - they're full of tips to help you get started and feel at ease in the water.
Water temperature
Participants in all distances must wear a swim hat plus a wetsuit and/or tow-float. Wetsuits are optional when the water temperature is between 16°C and 24.5°C. They are strongly recommended when the water temperature is below 15.9°C and mandatory when below 14.9°C. They are forbidden when the water temperature is 24.6°C or above. Wetsuit gloves and socks are allowed, but swimming aids such as snorkels and fins/flippers are prohibited.
Our wetsuit policy is set out in the table below.
| Mandatory | Strongly recommended | Optional | Forbidden |
|---|---|---|---|
| Below | Below | Between | Above |
| 14.9°C | 15.9°C | 16°C - 24.5°C | 24.6°C |
Water testing
Open water swimming differs from pool swimming as the water is both open to the elements and is not treated with chlorine. Rainwater, wildlife, warm weather or wildlife are among the many factors that can impact the water in outdoor swimming locations.
We test the water quality in the Serpentine Lake weekly in the lead-up to Swim Serpentine, so we can keep you informed about the conditions on Swim Day. You can view the latest on our water updates page.
